Mixing machines



April 26, 1966 J. H. C. ATKINS 3,248,092

MIXING MACHINES Filed OCT.. 17, 1963 3 Sheets-Sheet 1 5;/ imma", .aamsdnccul/ April 26, 1966 J. H. c. A'rKlNs MIXING MACHINES 3 Sheets-Sheet 2 Filed Oct. 17, 1963 April 26; 1966 J. H. c. ATKINS 3,248,092

MIXING MACHINES Filed OCT.. 17, 1963 1 3 Sheets-Sheet 3 ff M 5y l'saznzan, faazmau E' ofl/lcfulluc UnitedStates Patent O l 3,248,092 MIXING MACHINES John Harry Clapham Atkins, Stamford, Lincolnshire,

England, assignor, by mesue assignments, to Baker Per-v kins Holdings Ltd., Peterborough, England Filed Oct. 17, 1963, Ser. No. 316,980 Claims priority, application Great Britain, Oct. 24, 1962, 40,302/62 Claims. (Cl. 259-129) This invention relates to mixing machines, and more particularly to mixing elements for use therein. Such machines commonly comprise a mixing chamber into which ,extend yone or more suitably mounted, rotary mixing elements,vand, where two or more of such elements are used,vthese may be arranged to interact or inter-mesh so as to eliminate blind or dead spots within the mixing chamber.

`There are numerous known types of mixing elements, for example the worm type, which may have one or more starts, ,or the ribbon type .which comprises an axial shaft carrying helically extending members radially spaced from the shaft. Certain mixing elements are manufactured by forging processes, others being' manufactured as castings,- whilst ribbon type elements are normally produced in a prefabricated form, the helical blades being cut and formed from at plate and welded to or mounted on transverse discs or arms attached to the axial shaft. This method is time consuming and involves complicated jigging arrangements for the -welding operation, as well as accurate forming ofthe helical members.

An object of the present invention is to provide a si-rnplied mixing element for use in a mixing machine, the element being simpler and more economical to manufacture than known types whilst retaining their mixing efficiency.

The -invention consists in an element for a mixing machine or the like comprising an axial shaft, and one or more substantially flat mixing members or discs, each having an opening engageable with the shaft, at least one dimension of which is greater than the corresponding shaft dimension such that the disc may be tixedly attached to the shaft in a tilted position.

' a non transverse position with respect to the shaft axis.

The shaft of the mixing element according to the invention, may'be of any convenient cross section, the or each mixing disc being provided with a suitably shaped hole for threading onto the shaft, and each disc may be of any convenient shape and form, conductive to etiicient mixing. Furthermore, the discs may be aligned at the same or diiferent angles on the shaft (depending on the relative sizes of the holes formed therein) and adjacent discs may be tilted in the same or opposite directions.

The invention will now be described by way of an example, with reference to the accompanying drawings in which:

FIGURE 1 is a sectional side elevationof a' mixing machine,

FIGURE 2 is a sectional end elevation of the machine taken on line II-II of FIGURE 1,

FIGURE 3 is a plan view showing the true shape of the discs used for the mixing elements of the machine, and

FIGURES 4 to 6 show alternative forms of discs for the mixing elements.

Referring now to FIGURES 1 and 2, a mixing machine 1 is provided with a pair of intermeshing, rotary mixing elements 2 and 3 which extend into the mixing chamber 4 thereof.

3,248,092 Patented Apr. `26, 1966l or discs 7 and 8 respectively, each cut from a dat plateV and havinga shape similar to a rounded letter H with an enlarged central portion or cross-bar 10 which terminates in curved ends or limbs 11 and 12. The enlarged central portion 10 is provided with an elliptical hole 9 (see FIGURE 3), the minor axis of which is sutlicient to allow the disc to be threaded onto a shaft 5 or 6. The major diameter of the hole 9 allows the disc to be tilted with respect to the shaft thereby controllingthe angle at which .it is fixed to the shaft by welding. The elliptical hole may be centrally located with respect to the disc, or offset as shown, depending on the mixing effect required.

Thus the mixing elements 2 and 3 may be simply constructed by providing the shafts 5 and 6 each with a series of similar mixing discs, spaced apart and welded to the shaft at angles dependent on the relative sizes of their major diameters, and adjacent discs may be tilted in the same direction, or in opposite directions (as shown).

According to'the present example, the mixing machine is provided with a pair of parallel, spaced apart shafts, on each of which is a plurality of axially spaced, generally H-shaped mixing members or blades having limbs of unequal size or area and joined by a cross-bar. Alternate blades on each shaft are titled in opposite directions. Moreover, alternate `blades on each shaft have their larger area limbs disposed on opposite sides of the respective shaft. The blades on the shafts are axially staggered and the inter-element spacing A, see FIGURE 2, is such that the blades intermesh, in operation, to eliminate dead spots within the mixing chamber 4, and such that a small clearance is maintained between the rotating discs and the walls of the mixing chamber. The size or area of each of the longer limbs 12 is such that, when the blades are fixed on their respective shafts, the confronting ends of two adjacent limbs 12 will terminate in the same vertical plane transverse to the axis of the Thus, for example, any of the'alternative shapes shown Y in FIGURES 4 to 6 may be used. The angular position of the discs on the shaft need also not be constant and may vary from disc to disc. l

The mixing member shown in FIGURE 4 is substantially H-shaped having a pair of limbs 13 and 14 joined by a cross-bar 15 in which the opening 9 is located. The cross-bar 15 terminates at 'one end in a pair of branches 15a and 15b between which is a generally triangular opening 16. l

The -mixing member shown in FIGURE 5 also is substantially H-shaped in plan and comprises a pair of limbs 17 and 18 joined by a cross-bar 19 in which the hole 9 is located. In each limb is an opening 20.

The mixing member shown in FIGURE 6 also is substantially H-shaped in plan and includes a pair of limbs 21 and 22 connected by a cross-bar 23 in which the hole 9 is located. Each limb has an opening 24 therein.

Furthermore the shaft, whilst described as being of 'circular cross section, may be a square or rectangular,

afa-18,992

comparable in etliciency with other known types'of elements, and it has been found that the mixing effect of the element described above, may be practically identical to that obtained with a helical ribbon type element.V

Manufacture of elements of the type heretofore described, is extremely simple, the discs themselves acting as jigs inasmuch as the major diameter of the elliptical, or other suitably shaped hole, controls the angular setting of the disc with respect to the shaft. Some additional, simple form of jig may be required when Welding the discs to the shaft but such arrangements are simple as compared with the construction of other known types of pre-fabricated mixing elements.

I claim:

1. Apparatus for use in a -mixing or like machine comprising a pair of substantially parallel, spaced apart, rotatable shafts; a plurality of mixing members for each shaft, each of said mixing members being generally H-shaped in plan and having a pair of spaced apart limbs joined by a cross-bar,` the limbs and cross-bar of each of said mixing members being substantially co-planar, the cross-bar of each of said members having an opening therein through which its respective shaft extends, the opening in each of said members having a dimension vgreater than the corresponding dimension of its respective shaft whereby each of said members may be tilted relatively to its respective shaft; and means -xing each of said members on its respective shaftin axially spaced relation, the axial spacing of the members on each of said shafts and the spacing between said shafts being such to enable intermeshing of the members on said shafts in response to rotation thereof.

2. The construction set forth in claim 1 wherein one of said limbs of each of said members has an area larger than the other.

3. The construction set forth in claim 2 wherein alternate members have their larger area limbs disposed on one side of their respective shaft and theirsmaller area limbs on the opposite side of their respective shaft.

4. The construction set forth in claim 1 wherein alternate members on each of said shafts are tilted in opposite directions. Y

5. The construction set forth in claim 1 wherein the limbs of each of said members are of unequal area and wherein alternate ones of said members on each yof said shafts are tilted in opposite directions, and whereinV the confronting ends-of the larger area limbs-of two adjacent members on each of said shafts terminate in substantially the same plane transverse tothe axes of said shafts.

6. An element for a mixing machine or the like comi prising a rotatable shaft; a plurality Iof substantially planar shaft extends, at least one dimension of saidy opening in each of said mixing members being greater than the cori responding dimension of said shaft whereby each of said mixing `members may be tilted relatively to said shaft;

and means fixing each of said mixing members on said 1 shaft in axially spaced, tilted relation. 7. The construction set forth in claim 6 wherein alter nate mixingA members are tilted in opposite directions..`

8. The construction set Vforth in claim 6 wherein the larger area portionsof alternate ymixing members are located on opposite sides of said shaft.

9. The construction set forth in claim 6 wherein alternate mixing members are tilted in opposite directions and wherein thelarger area portions of alternate members` are located on opposite sides'of said shaft.

10. The construction set forthrin claim 9 wherein the 1 axial spacing between adjacent mixing members. is suchl that the confronting ends of the laregr area portions terminate in a common plane transverse to the axis of said WALTER SCHEEL, Primary Examiner. CHARLES A. WILLMUTH, Examiner. R. W. JENKINS, Assistant Examiner. 

1. APPARATUS FOR USE IN A MIXING OR LIKE MACHINE COMPRISING A PAIR OF SUBSTANTIALLY PARALLEL, SPACED APART, ROTATABLE SHAFTS; A PLURALITY OF MIXING MEMBERS FOR EACH SHAFT, EACH OF SAID MIXING MEMBERS BEING GENERALLY H-SHAPED IN PLAN AND HAVING A PAIR OF SPACED APART LIMBS JOINED BY A CROSS-BAR, THE LIMBS AND CROSS-BAR OF EACH OF SAID MIXING MEMBERS BEING SUBSTANTIALLY CO-PLANAR, THE CROSS-BAR OF EACH OF SAID MEMBERS HAVING AN OPENING THEREIN THROUGH WHICH ITS RESPECTIVE SHAFT EXTENDS, THE OPENING IN EACH OF SAID MEMBERS HAVING A DIMENSION GREATER THAN THE CORRESPONDING DIMENSION OF ITS RESPECTIVE SHAFT WHEREBY EACH OF SAID MEMBERS MAY BE TILTED RELATIVELY TO ITS RESPECTIVE SHAFT; AND MEANS FIXING EACH OF SAID MEMBERS ON ITS RESPECTIVE SHAFT IN AXIALLY SPACED RELATION, THE AXIAL SPACING OF THE MEMBERS ON EACH OF SAID SHAFTS AND THE SPACING BETWEEN SAID SHAFTS BEING SUCH TO ENABLE INTERMESHING OF THE MEMBERS ON SAID SHAFTS IN RESPONSE TO ROTATION THEREOF. 